The present invention relates to an inductive charger coupling for charging batteries such as batteries of electric vehicles.
As illustrated in FIGS. 11, 12 and 13, a prior art inductive charger coupling 100 includes a charging receptacle 100a and a charging paddle 100b. The paddle 100b is provided at an electric-power supply station. As illustrated in FIG. 12, the receptacle 100a includes a ferrite core 110, which forms a magnetic circuit, a secondary coil 120 wound about the core 110 and housing 130 for accommodating the core 110 and the secondary coil 120. The secondary coil 120 is manufactured by winding a wire of a conductive metal, such as copper.
The core 110 includes an upper core piece 110a and a lower core piece 110b, each of which has a generally E-shaped cross section as illustrated in FIG. 13. The combined core pieces 110a and 110b, or the core 110, form a center pillar 112 and side pillars 114a, 114b. The side pillars 114a, 114b are coupled to the center pillar 112 by bridge sections 116a, 116b, which forms a magnetic circuit.
The core 110 and the secondary coil 120 are fixed to the housing 130 by supporting members (not shown). The inner wall of the housing 130 and the core 110 define a space 132, which allows air to flow.
The housing 130 has inlets 134 formed in its upper and lower walls and a fan 140 attached to one end. Outlets 136 are formed next to the fan 140. Rotation of the fan 140 introduces air through the inlets 134 into the space 132 and discharges air from the outlets 136.
The magnetic paddle 100b includes an annular primary coil 150. When the paddle 100b is plugged into the receptacle 100a, the primary coil 150 is coaxially aligned with the secondary coil 129.
Alternating current supplied to the primary coil 150 induces current in the secondary coil 120. The induced current is supplied to a vehicle battery via a rectifier, which charges the battery. Charging of the battery, or the induction in the inductive charger coupling 100, heats the core 110 and the secondary coil 120. The fan 140 is actuated to move air through the space 132. The air cools the core 110 and the secondary coil 120.
Accordingly, the core 110 and the secondary coil 120 are cooled. However, the complex arrangement of the core 110 and the secondary coil 120 in the housing 130 complicates the air passage formed in the space 132. This increases the air resistance of the space 132, which hinders the flow of air through the space 132. As a result, the coil 110 and the secondary coil 120 are not efficiently cooled.
In order to efficiently cool the core 110 and the secondary coil 120, the number or the size of the inlets 134 and the outlets 136 may be increased. Alternatively, the space 132, which surrounds the core 110 and the secondary coil 120, may be enlarged to reduce the air resistance. However, larger inlets 133 and outlets 136 or an increased number of the inlets 133 and the outlets 136 increases the amount of electromagnetic energy escaping from the housing 130. That is, these measures will reduce the ability of the housing 130 to shield the electromagnetic waves generated by the core 110 and the secondary coil 120. On the other hand, enlarging the space 132 enlarges the size of the housing 130. This increases the size of the inductive charger coupling 100.
Further, dust may partly cover the inlets 134 and the outlets 136 or may enter the space 132. Dust at the inlets 134 and the outlets 136 and in the space 132 hinders airflow, thereby hindering the cooling of the core 110 and the secondary coil 120.